Poly(lactic acid)/TiO2 nanocomposites as alternative biocidal and antifungal materials

Abstract

Poly(lactic acid) (PLA) composites with titanium oxide (TiO2) similar to 10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased similar to 12% when 5 wt.% of TiO2 was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased similar to 54% compared to neat PIA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO2 nanocomposites showed lower shear viscosity than neat PIA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO2 composites with 8 wt% TiO2 showed a reduction of Escherichia colt colonies of similar to 82% under no UVA irradiation compared to pure PIA This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.%TiO2 killing 94% of the bacteria. The PLA/TiO2 nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation.